Research On Handover Process And Algorithms Of Td-Lte System In High-Speed Railway Environment

The purpose of this paper is to research on the problem of frequent dropping calls and poor signal quality of TD-LTE system in high-speed railway environment. The paper mainly discusses the parameters of handover measurement and handover decision in the handover process. The handover algorithms are proposed and the simulator is used to perform this process and illustrate algorithms and results. Firstly LTE system architecture, protocols, and handover process are analysed as a theoretical basis. In order to verify optimized algorithms, a simulation platform in a high-speed hilly environment is set up. For handover measurement process, a optimized algorithm about measurement parameter is proposed and verified in physical layer downlink level simulation platform. Moreover the simulation result is to evaluate the impact of channel environment and bandwidth on the RSRP and RSRQ measurement. To reduce the impact of the Shadow fading environment, the filter process is utilized. The filter parameters for the different speeds are determined by LTE system level simulation platform. Finally, the adaptive handover algorithm is proposed for high-speed hilly environment. The optimal combination of control parameters HO_Hyst and TTT under different speeds are achieved. In that condition the performance of the algorithm is verified. The algorithm can minimize the probability ping-pong handover and radio link failure, greatly improving the user experience.